1. Technical Field
The present invention relates to a lighting device provided with a light emitting diode (referred to as an LED, hereinafter) and a drive circuit section driving the LED.
2. Description of Related Art
Recently, a large number of lighting devices in which LEDs having the features of small size, power saving, and long life are applied to lighting are under development. In association with such application of LEDs to lighting, various kinds of techniques are proposed in the field of lighting.
For example, Japanese Patent Application Laid-Open No. 2001-243807 discloses an LED bulb in which the external appearance of a conventional incandescent bulb is maintained intact, that is, an LED is provided inside a so-called globe so that compatibility with the conventional incandescent bulb is improved.
Japanese Patent Application Laid-Open No. 2005-216495 discloses an LED unit with a base in which an LED and a power supply circuit converting an input voltage into a voltage for LED are accommodated in separate cases respectively so that a situation is avoided that the light output of the LED is reduced owing to heat generated by the power supply circuit.
On the other hand, in order to achieve a higher luminance in the lighting employing LEDs, LEDs need to be accumulated at high densities. As such, when LEDs are accumulated at high densities, a problem arises that heat generated by the LEDs themselves causes damage and degradation in the LEDs themselves and the board on which the LEDs are mounted. Nevertheless, in the LED bulb described in Japanese Patent Application Laid-Open No. 2001-243807 and the LED unit with base described in Japanese Patent Application Laid-Open No. 2005-216495, design consideration for resolving such a problem caused by heat generated by the LED is insufficient.
Further, Japanese Design Registration No. 1284116 discloses a design of a light emitting diode lamp having an LED and a heat sink in which a recess accommodating a power supply circuit is provided in the heat sink in a manner of communication with the outside.